L31 350 Build

[88WS-6]

While waiting for my car to sell I've been thinking of possible ways to revive it. One option that I found was this L31 short block:

http://www.skipwhiteperformance.com/detail.aspx?Item=L31

Doesn't necessarily need to be this exact one at this price (I can get it for $1200), but that short block (not really a short block because it comes without the cam/lifter/rockers) is a great start. From there I would need to figure out heads and a cam. Even if I get standard Vortec heads (maybe $300 each?) and a decent cam I will be spending less than a legit L31 short block so I'll save a little money. I will keep my TPI for now so I would get a Vortec TPI base ($400) and then just need some rockers and lifters.

L31 short block (kinda) - $1200
Vortec Heads - $600
Cam?
Vortec TPI base - $400

$2500 for everything would be awesome at this point.

Any cam ideas? Any flaws in my uneducated thoughts?





Just found some heads:

http://www.ebay.com/itm/96-99-CHEVY-VORTEC-L31-5-7-SBC-350-CYLINDER-HEADS-/170713020232?hash=item27bf49f748&item=170713020232&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr

[BonzoHansen]

So would you then be keeping it?

[88WS-6]

Yea. It pains me to see it in my driveway every day and I put way too much into that car to let it go for nothing. If someone offers me $3000 I'll take it, but with no interest so far I'm looking into try to save her.

[WildBillyT]

While waiting for my car to sell I've been thinking of possible ways to revive it. One option that I found was this L31 short block:

http://www.skipwhiteperformance.com/detail.aspx?Item=L31

Doesn't necessarily need to be this exact one at this price (I can get it for $1200), but that short block (not really a short block because it comes without the cam/lifter/rockers) is a great start. From there I would need to figure out heads and a cam. Even if I get standard Vortec heads (maybe $300 each?) and a decent cam I will be spending less than a legit L31 short block so I'll save a little money. I will keep my TPI for now so I would get a Vortec TPI base ($400) and then just need some rockers and lifters.

L31 short block (kinda) - $1200
Vortec Heads - $600
Cam?
Vortec TPI base - $400

$2500 for everything would be awesome at this point.

Any cam ideas? Any flaws in my uneducated thoughts?





Just found some heads:

http://www.ebay.com/itm/96-99-CHEVY-VORTEC-L31-5-7-SBC-350-CYLINDER-HEADS-/170713020232?hash=item27bf49f748&item=170713020232&pt=Motors_Car_Truck_Parts_Accessories&vxp=mtr

Keep in mind the short block is missing the oiling system and timing system. And pushrods. You have to factor that in to your build too.

[WildBillyT]

Have a look at this:

http://paceperformance.com/i-6484922-12530283-5-7l-l31-r-1996-2000-chevy-gmc-full-size-trucks-1996-2002-g-van-savannahexpress-vans-1996-1999-p-vans-over-8600-gvw-96-00-ck23-g-l31-99-p3-5-7r-cpi-hd.html

Maybe get it in and running as-is and then cam swap it, run a thinner head gasket for more compression etc later on.

[88WS-6]

Not a bad idea. I will try to use as many existing parts as I can but I'm assuming by your comment on oil and timing that they won't swap over.

Check this one out:

http://paceperformance.com/i-6484911-12520270-5-7l-350cid-lo5-k-1987-1995-chevy-gmc-full-size-trucks-g-van-1996-2002-p-van-over-8600-gvw.html


Will this L05 allow me to use my current TPI base since I'm assuming it has the older non-vortec heads?

I also saw that the L31 I originally linked to is 4 bolt main. Will that not match to my stock trans since my L98 is 2 bolt?

[88WS-6]

Wow that L05 has horrible heads... Pass.

I'd like to live my life without having to experience TBI and swirl port heads...

[WildBillyT]

Not a bad idea. I will try to use as many existing parts as I can but I'm assuming by your comment on oil and timing that they won't swap over.

Check this one out:

http://paceperformance.com/i-6484911-12520270-5-7l-350cid-lo5-k-1987-1995-chevy-gmc-full-size-trucks-g-van-1996-2002-p-van-over-8600-gvw.html


Will this L05 allow me to use my current TPI base since I'm assuming it has the older non-vortec heads?

I also saw that the L31 I originally linked to is 4 bolt main. Will that not match to my stock trans since my L98 is 2 bolt?

The tin may swap over (timing cover and oil pan) but you will want a new timing chain, oil pump, oil pickup, probably fasteners, etc. My point there is that incendentals may add up. And nothing is more depressing than a $250 Summit order with no glory parts in it... just bolts, oil, and gaskets. :mrgreen:

[88WS-6]

The tin may swap over (timing cover and oil pan) but you will want a new timing chain, oil pump, oil pickup, probably fasteners, etc. My point there is that incendentals may add up. And nothing is more depressing than a $250 Summit order with no glory parts in it... just bolts, oil, and gaskets. :mrgreen:

Haha true. I'll have to find out what exactly will swap over. Will my trans/flywheel be ok with the 4 bolt main L31 short block?

[WildBillyT]

Haha true. I'll have to find out what exactly will swap over. Will my trans/flywheel be ok with the 4 bolt main L31 short block?

Trans, yes. Flywheel/flexplate I am pretty sure but you may want to check. If not, that's not an expensive part to find used.

[88WS-6]

Stock flexplate should fit because L98 and L31 short block are both 1 piece rear main seal. Sound correct?

[WildBillyT]

Stock flexplate should fit because L98 and L31 short block are both 1 piece rear main seal. Sound correct?

To me, yes.

[88WS-6]

Ok so using the L31 actual short block:

L31 short block - $2000 (Jegs)

Vortec Base - $400


Ive read good things about the LT4 hot cam which matches the vortec heads well ($180 down the road).

LT4 Hot Cam Specs:
idle - 6000 rpm
@.05 in. - 218/228
.525/.525 with a 112 LS

[WildBillyT]

Ok so using the L31 actual short block:

L31 short block - $2000 (Jegs)

Vortec Base - $400


Ive read good things about the LT4 hot cam which matches the vortec heads well ($180 down the road).

LT4 Hot Cam Specs:
idle - 6000 rpm
@.05 in. - 218/228
.525/.525 with a 112 LS

Just make sure your heads can handle it. Vortec stuff is easily the best bang for your buck but the stock heads have some weak points that you must address.

[88WS-6]

Well the cam could be in the future. The stock L31 cam is pretty wimpy. The link below is a good read:

http://www.pacificp.com/forum/viewtopic.php?p=74784&highlight=787

L31 cam specs:
* Intake Lift- .414"
* Exhaust Lift-.428"
* Intake Duration @.050"- 191
* Exhaust Duration @ .050-196
* Lobe Centerline-111

According to a few sources, the vortec heads (062 cast) can flow up to .460 lift stock. I haven't been able to verify if the heads on this short block are the 062 cast.

L31 short block heads - 64cc,1.94" intake,1.50" exhaust

[WildBillyT]

Well the cam could be in the future. The stock L31 cam is pretty wimpy. The link below is a good read:

http://www.pacificp.com/forum/viewtopic.php?p=74784&highlight=787

L31 cam specs:
* Intake Lift- .414"
* Exhaust Lift-.428"
* Intake Duration @.050"- 191
* Exhaust Duration @ .050-196
* Lobe Centerline-111

According to a few sources, the vortec heads (062 cast) can flow up to .460 lift stock. I haven't been able to verify if the heads on this short block are the 062 cast.

L31 short block heads - 64cc,1.94" intake,1.50" exhaust


Not flow .460, they can handle .460 lift. But that's just the guide clearance. The valvesprings are too weak for more than stock.

I run 062 Vortecs :mrgreen:

[88WS-6]

Right sorry. I'll have to call and ask for the head cast number. What cam are you running?

[WildBillyT]

Right sorry. I'll have to call and ask for the head cast number. What cam are you running?

Flat tappet XE268 Comp.

[WayFast84]

This and gm's 330hp cam http://www.jegs.com/i/GM-Performance/809/12530282/10002/-1?parentProductId=813788

http://www.jegs.com/i/GM-Performance/809/24502476/10002/-1 edit scratch that, one is roller one is flat tappet.

[WildBillyT]

I just deleted a few posts because I made a mistake copying/pasting. WF has the right long block, the one I posted was a non-Vortec engine. Although he posted a flat-tappet 330hp cam for a roller motor, which is not right. Trust me, you want a hydraulic roller cam.

[88WS-6]

This is supposedly an L31 with worked vortec heads and the LT4 cam already. Worth the extra $1000, I don't know...

http://www.yearone.com/serverfiles/fbshopmain2.asp?pid=CT350PC1&hid=C26DK73495&cat=C&trk=22

[88WS-6]

I just deleted a few posts because I made a mistake copying/pasting. WF has the right long block, the one I posted was a non-Vortec engine. Although he posted a flat-tappet 330hp cam for a roller motor, which is not right.

The one you posted has vortec heads.

Wayfast posted up GM part 12530282 - GM Truck 1996-2000 3/4 and 1 ton pick ups (2 bolt main)

You posted GM part 12530283 - L31-R GM full size truck/van (4 bolt main)

Both motors have the same vortec heads, camshaft and compression.




I assume the 0282 is fine for my GTA. It's also $100 cheaper...

[WayFast84]

I just deleted a few posts because I made a mistake copying/pasting. WF has the right long block, the one I posted was a non-Vortec engine. Although he posted a flat-tappet 330hp cam for a roller motor, which is not right. Trust me, you want a hydraulic roller cam.

Yeah, gm uses that camshaft in the vortec crate motors just in roller form. If I could do this again that long block would've been a lot easier and I would've had a warranty. It's a great deal and you can always upgrade cams. The real problem here is I would want screw in studs and they might void warranty because of them.

Edit for a hundo get 4 bolt mains.

[WildBillyT]

The one you posted has vortec heads.

Wayfast posted up GM part 12530282 - GM Truck 1996-2000 3/4 and 1 ton pick ups (2 bolt main)

You posted GM part 12530283 - L31-R GM full size truck/van (4 bolt main)

Both motors have the same vortec heads, camshaft and compression.




I assume the 0282 is fine for my GTA. It's also $100 cheaper...

Whoops. I thought I posted the L05 link by accident.

For $100, go for the 4 bolt mains.

[WayFast84]

How much do the intakes run?

[88WS-6]

The Edelbrock TPI base is around $400-$450

[88WS-6]

This motor has worked Vortecs and a better cam for $550 more. 4 bolt main, roller 1 piece RMS

http://high-performance-engines.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=ATK&Product_Code=HP32

[WayFast84]

Who are they? Stick with a reputable shop or company. The gta will be good for mid 13's easy with a bone stock vortec motor.

[WildBillyT]

This motor has worked Vortecs and a better cam for $550 more. 4 bolt main, roller 1 piece RMS

http://high-performance-engines.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=ATK&Product_Code=HP32

I would look in to that. Looks like a 2 year unlimited mile warranty. But I have never heard of ATK before.

[88WS-6]

Heard of it from thirdgen.org. I'm trying to find reviews because it's a good deal. $550 more and you get 351hp 400tq dyno tested over the Jegs standard L31 short block's 255 hp 330tq

[WildBillyT]

Heard of it from thirdgen.org. I'm trying to find reviews because it's a good deal. $550 more and you get 351hp 400tq dyno tested over the Jegs standard L31 short block's 255 hp 330tq

Plus they will change components if you would like.

[88WS-6]

Very tempting. That's low low 13s in a 3300lb car.

[WayFast84]

Very tempting. That's low low 13s in a 3300lb car. if your car is set up right you should see 13's all day with any vortec combo.

[WildBillyT]

Very tempting. That's low low 13s in a 3300lb car.

Give them a call. You also never know if they will work with you a little bit on price.

[88WS-6]

if your car is set up right you should see 13's all day with any vortec combo.

I don't think that Jegs long block with 255hp 330tq would do 13s. That's just about where a stock L98 is.


Jegs customer service replied that the stock flexplate will work fine as will all accesories and ignition. They also said the cast number on the "headers" (I think he meant heads) is 12558060.

I will be calling ATK in a few hours to work on a price, get the head cast number from their motor and see if I can swap a TPI friendly cam with it.

I only found a few reviews for ATK, only one was bad but it was pretty bad:
http://www.thirdgen.org/techboard/aftermarket-vendor-review/481556-has-anyone-ever-heard.html

[88WS-6]

ATK said that they can't change cams or change the price on the motors. I saw ads from them to hire engine builders so I'm not really sure why this is...

Anyway, I contacted Carolina Machine Engines, a very reputable company, and they are going to price out a Vortec 350, 4 bolt main, 1 piece rear main seal long block with a TPI friendly cam. I'm also on the hunt for a used Holley Stealth Ram so I don't waste any money on my stock TPI.

[BonzoHansen]

Why not call Josh at JS and ask him what he can do for you? He knows TPI stuff very well. If I were building a TPI setup he'd be call #1 for me.

http://www.jsspeedandcustom.com/

[88WS-6]

I spoke with him and I have him and an engine as one option. I'm looking into this option to see if it's in my budget and what I could get through CME. With Josh, it's "here's my money, do the best job possible" and I am completely fine with that. I'm just looking into this other build to see what alternatives I have because I want to make sure I do this right and exhaust my possibilities. So much damn money...

[88WS-6]

Well it's looking like I will be doing one of these two options:

#1:
This L31 long block (http://paceperformance.com/i-6484922-12530283-5-7l-l31-r-1996-2000-chevy-gmc-full-size-trucks-1996-2002-g-van-savannahexpress-vans-1996-1999-p-vans-over-8600-gvw-96-00-ck23-g-l31-99-p3-5-7r-cpi-hd.html) - $2200 (with core charge)

This cam (http://www.cranecams.com/product/cart.php?m=product_detail&p=24200) - $426

Valve springs (http://www.cranecams.com/product/cart.php?m=product_detail&p=25988) - $246


Option #2:

Carolina Machine Engines (http://www.cmengines.com/se/search.aspx) rebuilt L98 "high torque version" long block with Vortec heads and LT1 B-body "police package" cam - $2000 (with core charge and upgraded valve springs for heads)


Both have Vortec heads which will require a different intake manifold to keep my TPI:

Vortec TPI Base (http://paceperformance.com/i-6063249-hi-flo-tpi-vortec-intake-manifold-edelbrock-3817.html) - $480

This base says it requires Edelbrock Hi-Flo runners (http://www.amazon.com/Edelbrock-3865-High-Flo-Intake-Manifold/dp/B000JFL1O0/ref=sr_1_fkmr0_3?s=automotive&ie=UTF8&qid=1328544951&sr=1-3-fkmr0) - $450

Instead of spending $930 on new Edelbrock TPI conversion parts, I would probably just get a used Vortec HSR for around the same price.

I'm leaning towards the CME option because I will be able to keep the warranty even with the LT1 cam and Vortecs. I'll void the GM warranty when I swap the tiny L31 cam. Everything is still in planning stages though.

Thoughts?

~Matt

[sweetbmxrider]

Why not shop local machine shops? Might spend a little more but you will get a motor built around what you want.

[WayFast84]

I would just call Josh for a custom built motor but you could also go with Paul at RPM if you went with the crate motor(he is closer to you and does awesome work).

If you do option number 1 measure the retainer to guide clearance FIRST and then order a camshaft. UPGRADE TO SCREW IN STUDS! Also remember that 1.6 ratio rocker arms need the pushrod holes machined and you can either go with guide plates and normal rockers or just self aligning rockers. Never both.

[88WS-6]

Why not shop local machine shops? Might spend a little more but you will get a motor built around what you want.

I have a request in with 3 different shops but so far no one that will be in budget and let me swap it. Promar is who Paul from RPM uses and they have this short block:

http://www.promarperformanceengines.com/short-block-engine-chevy-350-CI.asp


And this L31 4 bolt main long block:

http://www.promarengine.com/searchresults.asp?SelCat=++Engines:+General+Motors&txtType=Rebuilt%20Engines&txtPart=CH350-18

[WildBillyT]

Do you want an 87 octane engine?

[88WS-6]

Doesn't need to be. I'd run premium gas anyway.

[WildBillyT]

Doesn't need to be. I'd run premium gas anyway.

I am just asking since the 9.5:1 compression ratios seem a little low for a performance engine. With a higher static number you would get more out of a bigger cam.

[88WS-6]

I can't afford anything with more compression. That seems to be the main issue.

[88WS-6]

If anyone stumbles upon any good L98 motors, even short blocks, let me know. I wouldn't hesitate to take that option and have a running car again.

[WildBillyT]

I'd go with the Pace long block, personally.

How are you planning on returning the core? That may be something to consider if you have to crate it and send it back on your own dime.

[88WS-6]

I'll likely eat the core and try to sell my knocking short/long block.

[88WS-6]

And here's the other issue with a local builder. I've been quoted at the lowest, $2200 to rebuild my stock L98 bottom end and have a valve job on the heads. That doesn't include pulling the motor and replacing it.

[townsend]

id help you pull the motor im on furlough from work so i have nothing better to do lol

[88WS-6]

I'm now leaning towards finding a running L98 to just swap and get me going again. I don't feel like buying a $2000 re-conditioned L98 or a new truck motor which I will hopefully swap to a bigger faster engine in a few years. It makes more financial sense to spend as little now to get going since my car still needs paint and a headliner. Finding an f-body L98 would be preferred because it would keep me in a stock-ish auto-x class. A Corvette L98 swap would throw me to the dogs.

I should have titled this thread "No Idea What to Do, But I Need a New Engine and I'm Just Going to Post Every Idea I Have."

~Matt

[Anti_Rice_Guy]

I should have titled this thread "No Idea What to Do, But I Need a New Engine and I'm Just Going to Post Every Idea I Have."

~Matt

That can be arranged :mrgreen:

[WayFast84]

You can get running 305's for $100 just to get it going again.

[88WS-6]

Yea but it's a 305... I could probably get a running V6 for $50 too.

[88WS-6]

Maybe this will be an L31 build after all...

http://www.skipwhiteperformance.com/detail.aspx?Item=L31


Then I just have to find a used set of heads and a TPI friendly cam.

~Matt

[88WS-6]

Anyone have any input on World Products Sportsman IIs? Would my stock TPI intake bolt up and do I have angled plugs?

[WildBillyT]

Anyone have any input on World Products Sportsman IIs? Would my stock TPI intake bolt up and do I have angled plugs?

Old design. They are decent but you can do better these days. JMHO.

[JSPERFORMANCE]

In your messages to me you stated your budget was $2000.

This engine is $1500 + shipping I assume

You still need:
Cam
Lifters
Timing set
Gaskets
Seals
Your heads rebuilt (or a new set)
Oil pump
Pickup

All of this easily adds up past the $1000 mark if you rebuid your heads, way more if you go aftermarket.

So what is your actual budget?

[88WS-6]

In your messages to me you stated your budget was $2000.

This engine is $1500 + shipping I assume

You still need:
Cam
Lifters
Timing set
Gaskets
Seals
Your heads rebuilt (or a new set)
Oil pump
Pickup

All of this easily adds up past the $1000 mark if you rebuid your heads, way more if you go aftermarket.

So what is your actual budget?

It's $2000. I was hoping to get the block, and slowly piece the motor together while saving for the other parts. Still looking for a running L98 to swap in and get going too. I'm all over the place.